Discovery of novel N-phenylglycine derivatives as potent and selective β3-adrenoceptor agonists for the treatment of frequent urination and urinary incontinence

With a novel assay using isolated ferret detrusor to estimate beta (3)-adrenoceptor agonistic activity, we found that a series of glycine derivatives of ritodrine, a beta (2)-adrenoceptor agonist, are potent beta (3)-adrenoceptor agonists, with excellent selectivity versus beta1 and beta (2) subtypes. Substitution of halogens in the phenyl ring increased potency and selectivity for the beta (3)-adrenoceptor, and this was dependent upon the position of the halogens. The chlorine-substituted derivatives 3f-i exhibited potent beta (3)-adrenoceptor-mediated relaxation of ferret detrusor (EC50 = 0.93, 11, 14, and 160 nM) and higher potency at beta (3)-adrenoceptors than at beta (1) or beta (2) The intravenous administration of 3h significantly reduced the urinary bladder pressure in anesthetized male rats (ED50 = 48 mug/kg) without cardiovascular side effects. This article is the first report of structure-activity relationships (SAR) concerning beta (3)-adrenoceptor agonists as agents for the treatment of urinary frequency and incontinence.